The disclosure relates to a torsional moment and angle sensor for determining a torsional moment to be transferred from a drive member to a driven member as well as an absolute angle of rotation of the driven member. In particular, the disclosure relates to a torsional moment and angle sensor for determining a rotational angle and a torsional moment to be transferred from an activator drive from a processing plant such as a refinery, a foodstuff processing plant or the like, to a control valve, such as a pneumatically actuated ball valve of such a plant. The disclosure further relates to an actuator drive for a processing plant having a torsional moment and angle sensor for determining a torsional moment to be transferred from a drive member of the actuator drive to a driven member of the control valve of the processing plant and an angle of rotation of the control valve.
A known torsional moment and angle sensor in the field of automotive technology is disclosed in DE 100 41 090 A1. The known torsional moment sensor and the angle sensor comprises two encoder wheels arranged on very rigid steering shaft which are scanned for detecting a respective distortion angle of the encoder wheels by sensor elements that are fixed stationary with respect to the rotatable steering shaft. A torsional moment is calculated from the angle difference between the two encoder wheels. However, the known torsional moment and angle sensor has the disadvantage of that, due to the torsionally rigid steering shaft, two very precisely measuring angle sensors as well elaborate calibration and measurement correction methods are required in order to determine the torsional moment from the angle difference. If thereby one of the angle sensors fails, determining the torsional moment is no longer possible.